A backrest is known from DE 101 60 929 A1. The ends of the support rods for the headrest that extend into the backrest are connected to one another by a crossbar. These connections are designed as stop-lock connections, wherein one of the stop-lock connections can always be disengaged by applying the appropriate amount of pull, while the other stop-lock connection can be disengaged only by lifting a latch. The latter stop-lock connection has a z-shaped, bent leaf spring, which is positioned in a circumferential groove in the crossbar that encompasses a mounting opening for the support rod. When the support rod is pushed inward, the leaf springs yield elastically outward and then fall into two diametrically opposite notches that are equipped with locking surfaces for the stay bar and are arranged perpendicular to the direction of extension. In this position the headrest cannot be pulled out of the backrest. To allow this stop-lock connection to be disengaged, the support rod is rotatably mounted in the headrest. Furthermore, between the underside of the headrest and the upper surface of the backrest, unlocking surfaces for an open-ended wrench are provided. To disengage the stop-lock connection, the open-ended wrench is placed on the unlocking surfaces, and the support rod is rotated 90°. This frees the leaf springs from the notches in the stay bar and leaves them resting on its notchless; i.e., smooth circumferential area. The headrest can now be drawn upward out of the backrest.
The above-described construction is intended to prevent a headrest from being removed from a backrest, for example to improve the view toward the rear; in such cases it can be easy to forget to return the headrest to the backrest, leaving a passenger in the affected seat without the protection of a headrest.
A further backrest of this type is disclosed in DE 42 16 584 C2. However, with this backrest the stop-lock connection between the mounting devices and the support rods for the headrest are separable, so that the headrest can be removed from the backrest by a driver or passenger. This is precisely what the present invention seeks to prevent.